1. Field of the Invention
The present invention relates to an organic light emitting display device and, more particularly, to a transparent organic light emitting display device.
2. Description of the Related Art
Organic light emitting display devices have excellent characteristics in terms of angle of view, contrast, response speed, and power consumption, and thus are widely used in personal portable appliances such as MP3 players or mobile phones and TVs.
The organic light emitting display devices have self-emissive characteristics, and thus do not require a light source, unlike a liquid crystal display (LCD) device which does require a light source. Accordingly, the thickness and weight of the organic light emitting display device can be reduced.
Also, a transparent organic light emitting display device may be formed by inserting a transparent thin film transistor (TFT) or a transparent organic light emitting device thereinto.
However, in a transparent organic light emitting display device, an object or an image that is positioned on the opposite side of the user is transmitted through not only an organic light emitting device but also patterns like a TFT, various wirings, and spaces between them in a switched-off state. In addition, even when the organic light emitting display device is a transparent display device, the transmittivity of the organic light emitting device, the TFT, and the wirings described above is not high, and the spaces between them are very small. Accordingly, the transmittivity of the organic light emitting display device is not high.
Also, the user may see a distorted image due to the patterns described above, that is, the organic light emitting device, the TFT, and the wirings. Since distances between the patterns are several hundred nanometers, which is the same as a visible light wavelength, diffusion of light that has been transmitted occurs.
Meanwhile, compared to an LCD device, a both (bottom and top) emission type display device may be easily manufactured using the organic light emitting display device.
However, since the reflective anode cannot be used in the both emission type display device, optical resonance effects may not be used, which makes it difficult to obtain a high outcoupling efficiency. If a transparent anode is changed to a semi-transmissive anode to increase the outcoupling efficiency of the both emission type display device, the transmittivity of the organic light emitting display device is lowered. Thus, it is difficult to manufacture a transparent organic light emitting display device.